It is common practice to use Lighting fixtures employing fluorescent lamps, to provide the main lighting of large and small spaces, replacing or complementing incandescent lights in the majority of commercial and industrial applications.
Fluorescent lighting fixtures are commonly made to direct the lamp light downward towards the floor or upwards towards the ceiling or in a combination of both to meet the particular user needs in offices, stores, mass merchandizing areas or factories, wherever fluorescent lights are used
It is also common to use reflectors behind the lamps and diffusers in front of the lamps to control where the emitted light is being directed and to place the electrical components in special sides of the fixtures.
It is common also to install fluorescent luminaries in long linear lines due to the limited number of lamps, usually 4 to 6 that the lighting fixture can accommodate side by side in the standard 2 foot wide fixture size used by the industry.
The disadvantages of the present practice are that a larger number of fixtures are required per installation due to the fewer lamps each fixture can accommodate. The limited possibilities of installing the fixtures over the space to be lighted except in end to end in long rows and the limitation of the fluorescent fixture applications to low and medium height ceilings of about 15 to 20 ft due to the small number of lamps per fixture, and the time and cost of individually mounting or changing the electrical components inside the fixture.
It is also common practice at present, to use two types of fluorescent fixtures in the same commercial space, one to provide the general space lighting and another lighting fixture to display commercial messages or directional signs on the sides of that fixture.
The disadvantage of these special illuminated display fixtures is that they are expensive, require special independent installation and they add to the cost of the lighting installation and are only visible in the direct areas where they are installed.
Examples of the prior art are U.S. Pat. No. 6,024,468 (issued Feb. 15, 2000, Kassay et al) and U.S. Pat. No. 6,428,183 B1 (Aug. 6, 2002, McAlpin).
Improvements are continuously sought to improve optical efficiency and to reduce cost of luminaries.